1. Field of the Invention
The present invention relates to a method for manufacturing the face component of a golf club head. More specifically, the present invention relates to a method for manufacturing a golf club head composed of a two-piece face component, including a cast return section and formed face insert.
2. Description of the Related Art
When a golf club head strikes a golf ball, large impacts are produced that load the club head face and the golf ball. Most of the energy is transferred from the head to the golf ball, however, some energy is lost as a result of the collision. The golf ball is typically composed of polymer cover materials (such as ionomers) surrounding a rubber-like core. These softer polymer materials having damping (loss) properties that are strain and strain rate dependent which are on the order of 10–100 times larger than the damping properties of a metallic club face. Thus, during impact most of the energy is lost as a result of the high stresses and deformations of the golf ball (0.001 to 0.20 inches), as opposed to the small deformations of the metallic club face (0.025 to 0.050 inches). A more efficient energy transfer from the club head to the golf ball could lead to greater flight distances of the golf ball.
The generally accepted approach has been to increase the stiffness of the club head face to reduce metal or club head deformations. However, this leads to greater deformations in the golf ball, and thus increases in the energy transfer problem.
Some have recognized the problem and disclosed possible solutions. An example is Lu, U.S. Pat. No. 5,499,814, for a Hollow Club Head With Deflecting Insert Face Plate, discloses a reinforcing element composed of a plastic or aluminum alloy that allows for minor deflecting of the face plate which has a thickness ranging from 0.01 to 0.30 inches for a variety of materials including stainless steel, titanium, KEVLAR®, and the like. Yet another Campau invention, U.S. Pat. No. 3,989,248, for a Golf Club Having Insert Capable Of Elastic Flexing, discloses a wood club composed of wood with a metal insert.
Although not intended for flexing of the face plate, Viste, U.S. Pat. No. 5,282,624 discloses a golf club head having a face plate composed of a forged stainless steel material and having a thickness of 3 mm. Anderson, U.S. Pat. No. 5,344,140, for a Golf Club Head And Method Of Forming Same, also discloses use of a forged material for the face plate. The face plate of Anderson may be composed of several forged materials including steel, copper and titanium. The forged plate has a uniform thickness of between 0.090 and 0.130 inches.
Another invention directed toward forged materials in a club head is Su et al., U.S. Pat. No. 5,776,011 for a Golf Club Head. Su discloses a club head composed of three pieces with each piece composed of a forged material. The main objective of Su is to produce a club head with greater loft angle accuracy and reduce structural weaknesses.
Certain existing golf club heads have a metallic cup-shaped face component that is joined to a composite or metal body. The face component, which includes a striking face and a rearwardly extending flange, is currently forged as a single piece. The process of forging the face component, however, has several limitations in terms of wall thicknesses that can be achieved around the flange. It is not possible to forge face components with a very thin (less than 0.050 inch thickness) flange or a transition region between the striking face and the flange. These design considerations lead to very short tool life in forging and thus increase the cost of making such face component shapes.
A face component with a thinner walled flange and transition region than current face component provides several advantages. First, the weight removed from the thinner face component may be strategically redistributed to other areas of the club head to enhance the playing characteristics of the golf club head. Second, the thinner wall in the transition region between the striking face and the flange allows for more deflection of the face, thereby improving it's coefficient of restitution. Although the prior art has disclosed many variations of multiple material club heads, the prior art has failed to provide a multiple material club head with a high coefficient of restitution at a lower production cost.